Although illicit use of narcotics is widespread in our culture, and although there have been many studies on biochemical and behavioral effects of narcotics, we still know very little about their action on brain cells. One of the most meaningful indicators of brain cell function is nerve impulse activity; surprisingly, few investigators appear to have studied this aspect of narcotic action. Therefore, I am proposing to use this novel approach to improve our understanding of how narcotics effect brain function and behavior. Specifically, this research will attempt to discover regional differences in sensitivity to narcotics. Narcotic effects will be assessed by recording impulse activity from a small population of neurons simultaneously from at least seven different brain areas in a given animal, before and after injection of low doses of narcotics. Impulse activity in brain areas which are especially sensitive to narcotics will be studied during addiction and withdrawal. Impulse recording will also serve as an assay system for testing narcotic blockers and their analogs. This approach is important because it can pinpoint those portions of the brain which are the primary targets of narcotic action. Once this information becomes available, we will have greater chances for success in identifying which neurochemical reactions mediate the narcotics action. Once the target neurochemical reactions are identified, we will have improved chances of developing compounds that may cure narcotic addiction.